Molecular beacon

Molecular beacons are hairpin-shaped molecules with an internally quenched fluorophore whose fluorescence is restored when they bind to a target nucleic acid sequence.

When the beacon is in closed loop shape, the quencher resides in proximity to the fluorophore, which results in quenching the fluorescent emission of the latter.

If the nucleic acid to be detected is complementary to the strand in the loop, the event of hybridization occurs.

The presence of the emission reports that the event of hybridization has occurred and hence the target nucleic acid sequence is present in the test sample.

Fluorogenic signaling oligonucleotide probes were reported for use to detect and isolate cells expressing one or more desired genes, including the production of multigene stable cell lines expressing heteromultimeric epithelial sodium channel (αβγ-ENaC), sodium voltage-gated ion channel 1.7 (NaV1.7-αβ1β2), four unique γ-aminobutyric acid A (GABAA) receptor ion channel subunit combinations α1β3γ2s, α2β3γ2s, α3β3γ2s and α5β3γ2s, cystic fibrosis conductance regulator (CFTR), CFTR-Δ508 and two G-protein coupled receptors (GPCRs).

Structure of molecular beacons in their native conformations (top) or hybridized with a DNA strand (bottom)
The structure of a typical molecular beacon probe